Metaphysics & Free Will and Determinism

Question 1

Qualitative Identity

Answer 1

To say X and Y are qualitatively identical is to say they are exactly similar.

Question 2

Numerical Identity

Answer 2

To say that X and Y are numerically identical means they are one and the same thing. E.g. a seedling that grows into a tree.

Question 3

The Law of Non-contradiction

Answer 3

A fundamental law of logic that a statement and its denial cannot both be true at the same time.

Question 4

Equivocation

Answer 4

Using an ambiguous term in more than one sense, thus making an argument equivocal.

E.g.:
P1: Noisy children are a headache.
P2: Two aspirin will make a headache go away.
C: Therefore, two aspirin will make children go away.

Question 5

Paradox

Answer 5

A collection of claims that seem plausible individually, but collectively seem logically impossible or absurd. Can involve a contradiction.

Question 6

Physical Possibility/Impossibility

Answer 6

Physical possibility is compatible with physical laws, physical impossibility isn’t.

Question 7

Logically Possible

Answer 7

A logically possible proposal cannot be self-contradictory.

Question 8

Logical Impossibility

Answer 8

A logically impossible proposal is self-contradictory. E.g. the earth is both a sphere and a cube.

Question 9

Personal Time

Answer 9

Roughly that which is measured by a time traveller’s wristwatch.

Question 10

Four Dimensionalism

Answer 10

Block Universe Theory + Perdurantism

Question 11

Perdurantism

Answer 11

• Objects and persons perdure/pesist over time and have temporal parts/stages.
• In one given moment, only one temporal part of an object/person exists.
• All temporal parts in the lifetime constitutes to the whole.

Question 12

Block Universe Theory

Answer 12

• Present is real and exists - its special status an illusion.
• No significant distinction between past, present and future.
• Past and future are real and exist but are fixed.
• Doesn’t acknowledge any passing/flow of time.

Question 13

Endurantism

Answer 13

A person/object endures over time. They are wholly present at every moment of their existence.

Question 14

Lewis’ solution to all arguments against time travel

Answer 14

“Not an impossibility, just an oddity…”

Question 15

Time Discrepancy Argument Against Time Travel

Answer 15

P1: if time travel is possible it must be possible for the time separating Tim’s departure from Tim’s arrival to be both 5 mins and not 5 mins but 40 yrs
P2: It is not possible for the time separating Tim’s departure from Tim’s arrival to be both 5 mins and not 5 mins but 40 years
C: Therefore time travel is not possible

Question 16

Lewis’ solution to the time discrepancy argument

Answer 16

No contradiction. Time separating Tim’s arrival from Tim’s departure is 5 mins relative to personal time and 5 mins relative to external time. Both can be true.

Question 17

Identity crisis Argument against time travel

Answer 17

P1: if time travel is possible it must be possible for the same person to be present in more than one location at the same time
P2: it is not possible for the same person to be present in more than one location at the same time
C: therefore time travel is not possible

Question 18

Lewis solution to the identity crisis paradox

Answer 18

If we accept four-dimensionalism which includes Perdurantism it is possible for two temporal parts of one numerically distinct person to be in two locations at the same time with no contradiction

Question 19

Closed causal loops argument against time travel

Answer 19

P1: if time travel is possible, then closed causal loops and other inexplicable events must be possible
P2: It is not possible for there to be closed causal loops or other inexplicable events
P3: therefore time travel is not possible

Question 20

Lewis solution to the closed causal loops argument against time travel

Answer 20

P1: closed causal loops, god, Big Bang, universes entire past and decay of a tritium atom are uncaused and inexplicable
P2: we accept god, Big Bang, universes entire past and decay of a tritium atom are possible
C: therefore we should also accept that closed causal loops are possible

Question 21

Grandfather paradox against time travel

Answer 21

P1: if time travel is possible, then Tim both can and cannot kill his grandfather
P2: It is not possible that Tim both can and cannot kill his grandfather
C: therefore time travel isn’t possible

Question 22

Lewis solution to the grandfather paradox

Answer 22

Can is equivocal. Relative to a narrow set of facts, Tim can kill his grandfather, Tim can kill his grandfather, but relative to a broader more inclusive set of facts Tim cannot kill his grandfather. Both can be true with no contradiction

Question 23

Logical contradiction

Answer 23

Putting forward a statement and its own denial simultaneously. Conjunction of P with its own denial of not-P.

Question 24

Physically possible ways of time travel (scientifically)

Answer 24

• Wormholes
• Black holes
• Travelling near speed of light

Question 25

External time

Answer 25

Public or objective time

Question 26

Temporal ordering

Answer 26

Events in order of time taken place in external time. When ranking, events in 1930 are earlier than events in 1990

Question 27

Causal ordering

Answer 27

Events in order of causes before effects. E.g. punch comes earlier than black eye

Question 28

Logical contradiction

Answer 28

When statements involve no logical contradiction

Question 29

Presentism

Answer 29

- Only the present and present things exists (events, objects, people) exist - the past no longer exists and is unchangeable - future is yet to exist and undecided/many possibilities - time passes with a distinct present moving forward into future and leaving past behind

Question 30

Horwich’s objection to Lewis grandfather paradox solution

Answer 30

P1: if tim travelled to 1921, there would be long strings of coincidences that would get in the way of Tim killing grandfather (e.g. slips on banana peel) P2: we never observe such long strings of coincidences P3: something we never observe is unlikely C: therefore time travel is unlikely but not impossible

Question 31

Smiths reply to Horwich’s objection

Answer 31

P1: In our current context it is true coincidences are observed rarely P2: however contexts involving time machines are unlike our current context, such coincidences may prove to be regular occurrence C: therefore observations in our current context or no basis for contexts involving time travel